The specific hydroquinone as shown in formula (I) is known as a skin lightening compound. See WO9523780. ##STR2## wherein Z is oxygen or sulfur.
The combination of the specific hydroquinone derivatives and penetration enhancers is disclosed in WO9523780.
WO9523780 describes that penetration enhancers are disclosed in Mahjour, M., B. Mauser, Z. Rashidbaigi & M. B. Fawzi, "Effect of Egg Yolk Lecithins and Commercial Soybean Lecithins on In Vitro Skin Permeation of Drugs", Journal of Controlled Release, Vol. 14 (1990), pp. 243-252. The journal discloses Lecithin as a penetration enhancer. However, there is no description of a liquid crystal comprising specific hydroquinone derivatives and lecithin which have penetration enhancing effect.
It is an object of the present invention to provide compositions for lightening mammalian skin which has a good penetration effect, so that the specific hydroquinone derivatives which are skin lightening actives can penetrate effectively and work effectively.